Cam block actuator



Jan. 29, 1957 H, EV NS 2,779,248

CAM BLOCK ACTUATOR 5 Sheets-Sheet 1 Filed Aug. 28, 1953 Jan. 29, 1957 v C STEVENS 2,779,248

CAM BLOCK ACTUATOR 3 Sheets-Sheet 2 fig 4 36 5O 50 69 Filed Aug. 28, 1953 74 7e 5O 2 32 34) 92 y; v. 85 I36 I00 98 E 4 as a 5 K 66 as INVENTOR.

Ehtg las H- EI LELVELTLEx ,4 TTOENEI Y5 Jan. 29, 1957 c, STEVENS 2,779,248

CAM BLOCK ACTUATOR Filed Aug. 28, 1953 3 Sheets-Sheet 3 I N VEN TOR.

Chufl as H Eli Evans A TTOENEYS Un t 2,779,248 CAM BLOCK ACTUATOR Charles H. Stevens, Springfield, Mass., assignor to the .United States of America as represented by the Secretary of the Army The invention described hereinmay be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

My invention relates to an electrically fired revolvertype automatic weapon and more particularly to the actuator for rotating the cartridge drum of such a Weapon.

Such a weapon ordinarily comprises a receiver with a recoil unit slidable therein including a barrel and a cartridge drum having peripherally spaced stub shafts thereon with the axes thereof intersecting the axes of the cartridge chambers of the drum. The drum is rotatably mounted on the recoil unit to convey the cartridge chambers successively to a firing position of the drum aligned with the barrel. An actuator, slidable on the receiver, is biased to a battery position and provided with grooves for'engaging the rollers to locate the chambers.

The grooves include a straight groove for retaining a chamber in the firing position when the actuator is in battery position and curved outlet and inlet grooves extending oppositely from the straight groove. The actuator slides in' an indexing cycle of rearwardand forward strokes responsive to discharge of the cartridge in the firing position chamber. A tongue pivoted on the actuator consecutively connectsthe outlet and-inlet grooves to the straight groove during the rearward and forward strokes to remove the chamber with the spent cartridge from the firing-position and to rotate the succeeding chamber into the firing position.

l The tongueis rotated by a separate cam'mounted ,on

the recoil unit, by means of a switch pin secured to the tongue and projecting through an arcuate slot in the actuator to engage a guide surface of the cam.

* In the weapon described, the strain ofaccelerating and decelerating rotation of the drum falls on the pivot and actuator means for rotating the drum of'such aweapon.

An additional object of my invention isto'provide a:

device for rotating the drum of such a weapon including positively actuated blocks for directly transmitting forces between the actuator and the drum.

Other aims audobjects of my invention 'will appear in the subsequent description.

ln carrying out my invention, "the actuator 'of -a gun similar'to that described above includes-similar"roller guide grooves" and the receiver is provided with a cam.

The actuator includes outletandinletblockSslidablydisposed therein having followers for engaging the cam to 2,779,248 lfatented Jan. 29, 19 57 Fice insure positive operation of the blocks and bearing surfaces for simultaneous engagement with the actuator and the rollers. The blocks arealternately moved to and from roller engagement positions as the actuator moves in the rearward and forward strokes of the indexing cycle. In the engagement positions, the roller bearing surfaces of the blocks respectively connect the curved grooves with the straight groove to control rotation of the drum by direct transmission of forces between the rollers and, the actuator. q r H I v For a better understanding of my invention, reference is directed to the accompanying drawing in which:

Fig. l is a perspective view of an electrically fired revolver-type automatic weapon including one embodiment of my invention;

Fig. 2 is a partly cutaway elevation view of the Weapon;

Fig. 3 is a view along the line 33 of Fig. 2;

Fig. 4 is a view along the line 44 of Fig. 2;

'Figs. 5 and 6 are views along the corresponding lines of Fig. 4; Fig. 7 is a partial perspective view of the actuator of the weapon; and v Fig. 8 is an exploded view of the outlet and inlet blocks and the cam. 3

As shown in the drawing, a weapon 12 is provided with a receiver 14 including sides 16 and an end 18 substantially perpendicular to a flat base 20. Pairs of mounting trunnions 22 and 24 are perpendicularly secured to sides 16.

A recoil unit slidable on receiver 14 includes abarrel 26 provided with a bore axis 27 and secured to a cradle 28. Barrel 26 is slidably disposed in a support 30 of receiver 14, and cradle 28 includes a pair of feet 32 slidable in corresponding grooves 34- vof receiver 14. .,.A cartridge drum 36 including chambers 38 is rotatably mounted on a shaft 4i! journalled at 42 and 44 in cradle 28. Chambers 38 are loaded by a feeder mechanism represented generally by a housing 45.

Weapon 12 is shown in battery position in Fig. 1 with the chamber 38 in the six oclock firing position of drum 36 in alignment with barrel 26 and with a cartridge 46 shown in position in the chamber. Drum 36 is provided with radial stub shafts 48 projecting from the surface thereof and intersecting the axes of chambers 38. rollers 50 are rotatably disposed on shafts 48.

Barrel 26 and receiver 14 respectively include passages 52 and 54 communicating between barrel 26 and a tube 56 slidably disposed between receiver 14 and a cylinder 58 of cradle 28. Cylinder S8 incloses a piston 60 secured to a plunger 62 projecting rearwardly from cylinder 58. An actuator 64, slidably disposed on receiver 14 by means of projections 66 extending into channels 68 parallel to axis 27, is biased to a battery position in engagement with plunger 62 by a pair of bulfer springs 79 engaging end 18. Springs 70 are guided by rods 71.

Actuator 64 is provided with grooves for guiding roll- Index ers 59 including a straight groove '72 parallel to channels 68 for selectively retaining chambers 38 in alignment 7 with barrel 26 when actuator 64 is in the battery position thereof and a pair of curved outlet and inletgrooves 74 and 76 of equal section for engaging rollers 50, oppositely extending from straight groove 72. Grooves 74 and 76 separate actuator 64 into a pair of forward and rearward lands 78 and 80 secured to a body 82. The lauds include an interrupted surface 84 concentric with drum 36. An aperture 86 provided in land 80 forms an inverted T-sl ot 'with a portion of straight groove 72; 1 f

Outlet and inlet blocks 88 and 90 are slidably disposed in a pair of corresponding sockets 92 in body 82. The

sockets communicate with aperture 86. Blocks 8S and 90 respectively include a pair of spring-biased follower pins 94 and 96 for projecting into tracks 98 and 1% of a cam 102. The cam is secured to base 20 and projects between the blocks.

Tracks 98 and 100 respectively include upper branches 104 and 106 and lower branches 168 and 116. Branches 104 and 108 of cam 102 are respectively connected forwardly and rearwar'dly to join intermediate sections 112 and 114 and branches 1G6 and 110 of cam 300 are connected to similar sections 116 and 118.

Curved surfaces 120 and 122 provided on blocks 38 and 90 respectively are positioned for engagement with rollers 50 when the corresponding pins are respectively restrained in the upper branches. In the engagement positions, curved surfaces 120 and 122 respectively connect grooves 74 and 76 with straight groove 72. Blocks 8% and 9% are depressed out of their respective engagement positions when pins 94 and 96 are respectively engaged by lower branches 108 and 11%. As shown in Fig. 4, blocks 88 and 90 are respectively in positions of roller engagement and disengagement.

Weapon 12 is electrically fired, and at the moment of discharge, pins 94 and 96 are respectively engaged by end sections 112 and 116. Gases from the discharge of the cartridge 46 in the firing position chamber escape from barrel 26 through passages 52 and 54 and tube 56 to force piston 66, plunger 62, and consequently actuator 64, rearwardly. As actuator 64 slides against buffer spring 70, pin 94 is progressively engaged by connecting groove 124 and groove 104 to raise block 88 to the engagement position thereof to allow the roller corresponding to the spent cartridge roller 50 to be guided from actuator 64 by curved surface 120 and outlet groove 74. Simultaneously, pin 96 is progressively engaged by connecting groove 126 and groove 110 to depress block 90 below the engagement position thereof.

End sections 11.4 and 118, respectively, allow overtravel for pins 94 and 96 and thus compensate for differences in charges of cartridges 46.

As cartridge 46 leaves barrel 26, gas pressure is released and actuator 64 slides forwardly responsive to springs 70, with pin 96 constrained by upper branch 106. During this time, roller 50 succeeding the spent cartridge roller is guided by successive engagement with curved groove 76 and curved surface 122 into firing position engagement with straight groove 72. During the latter portion of the stroke, pin 96 traverses groove 134 and enters end section 116 as actuator 64 returns to battery position. Simultaneously, pin 94 progresses through lower groove 108 and groove 132 to end section 112.

Bearing surfaces 136 and 138 on blocks 83 and 90, respectively, contact actuator 64 in the engagement positions for direct transfer of forces between the actuator and rollers 50. The floors of tracks 98 and 100 respectively include steps 140, 142 and 144, 146 to permit passage of rollers 94- and 96 through the tracks in the directions described only.

The cam arrangement described is of great advantage in weapon construction, since blocks 88 and 90 controlling rotation of cartridge drum 36 are positively guided instead of being spring-controlled as in other weapons. In addition, the blocks are supported by the actuator structure to transmit forces between the actuator and the drum rollers.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. in a. revolver-type automatic weapon having a receiver, a recoil unit slidable thereon provided with a rotatable drum having cartridge chambers and corresponding index rollers, and an actuator for rotating the drum slidably disposed for axial reciprocation on the receiver, a device for engaging the drum comprising outlet and inlet blocks respectively slidably disposed on the actuator and provided with roller engagement surfaces, and means for positively moving said blocks to and from positions thereof in direct engagement between the rollers and the actuator responsive to the axial reciprocation.

2. In a revolver-type automatic weapon having a receiver, a recoil unit slidable thereon provided with a rotatable drum having cartridge chambers and corresponding radially disposed index rollers, and an actuator for rotating the drum slidably disposed for axial reciprocation on the receiver, a device for engaging the drum comprising outlet and inlet blocks respectively slidable on the actuator and provided with surfaces for engagement with the rollers and cam means disposed on the receiver and said blocks for positive movement thereof to and from positions for direct engagement between the actuator and the rollers during relative movement of the recoil unit and the actuator.

3. In a revolver-type automatic weapon having a receiver, a recoil unit slidable thereon provided with a retatable drum having cartridge chambers and corresponding index rollers, and an actuator for rotating the drum slidably disposed for axial reciprocation on the receiver, a device for engaging the drum comprising outlet and inlet blocks respectively mounted in slidable relation with the actuator and provided with cam followers and surfaces for engagement with the rollers, and a cam disposed on the receiver between said blocks and provided with cam tracks for receiving said followers to alternately move said blocks into positions of direct engagement between the rollers and the actuator, during relative movement of the recoil unit and the actuator.

4. In a revolver-type automatic weapon having a receiver, a recoil unit slidable thereon provided with a rotatable drum having cartridge chambers and corresponding radially axised index rollers, and an actuator for rotating the drum slidably disposed for axial reciprocation on the receiver and provided with a straight groove and curved inlet and outlet grooves for engaging the rollers, a device for engaging the drum comprising outlet and inlet blocks provided with bearing surfaces and follower pins and slidably disposed on the actuator, and a cam mounted on the receiver and provided with a pair of tracks for engaging said pins to alternately convey said blocks to and from positions for direct engagement between the actuator and the rollers, during the reciprocation, said bearing surfaces being constructed to respectively connect said curved grooves with said straight groove in said engagement positions.

5. In a revolver-type weapon having a receiver, a recoil unit slidable therein, a drum with cartridge chambers and corresponding index rollers, and an actuator disposed in the receiver for slidable axial reciprocation to rotate the drum, a device comprising outlet and inlet blocks disposed for compressive engagement between the actuator and the rollers, and means for consecutive positive displacement of said blocks to and from positions for said compressive engagement responsive to said reciprocation.

6. In a revolver-type automatic weapon having a receiver, a recoil unit slidable thereon provided with a rotatable drum having cartridge chambers and corresponding radially axised index rollers, and an actuator for rotating the drum slidably disposed for axial reciprocation on the receiver, a device for engaging the drum comprising outlet and inlet blocks respectively mounted in slidable relation with the actuator and provided with cam followers and roller bearing surfaces, and a cam disposed on the receiver between said blocks and provided with oppositely disposed cam tracks for simultaneously receiving said followers, said tracks each including upper and lower bfaiiches for alternately guiding said bearing surfaces for roller engagement and disengagement during relative movement of the recoil unit and the actuator, in- References Cited in the file of this patent termediate sections to join said branches in loops and end UNITED STATES PATENTS sections for respectively engaging the follower in battery position and in overtravel of the actuator, said followers g f 5 aeg en Jan. 11, 9

and sand tracks being respectively provided with cooper ating spring tips and steps to permit progress of each FOREIGN PATENTS of the followers in but a single sense inthe loop corre- 285,180 Switzerland Dec. 29, 1952 spending thereto. 288,467 Switzerland May 16, 1953 

